1.) Is it possible to get over something like stage fright through lucid dreams?
For example, If I were to create a scenario where I was playing my bass(Solo bassist by the way) in front of thousands of people would it make playing small crowds such as a coffee shop easier in reality?

2.) This also has to do with music. If I made a dream where I had my computer with all the music tabs I needed to learn a song and practiced while in that dream non-stop would I be able to somehow pass that knowledge into my long-term memory bank?

I understand that the more you have practiced dream recall the more details you can remember but can you actually remember something as detailed as a song?